While researching her new book, Girls & Sex, Orenstein spoke with more than 70 young women between the ages of 15 and 20 about their attitudes and early experiences with the full range of physical intimacy.

She says that pop culture and pornography sexualize young women by creating undue pressure to look and act sexy. These pressures affect both the sexual expectations that girls put on themselves and the expectations boys project onto them.

Orenstein adds that girls she spoke to were often navigating between being considered "slutty" or a "prude," and that their own desires were often lost in the shuffle. Girls, Orenstein says, are being taught to please their partners without regard to their own desires.

"When I would talk to girls, for instance, about oral sex, that was something that they were doing from a pretty young age, and it tended to go one way [and not be reciprocated]," Orenstein explains.

Orenstein recommends that parents examine the messages they send regarding girls and sexuality. "One of the things that I really took away from this research, is the absolute importance of not just talking about [girls] as victims, or not just talking about them as these new aggressors, but really surfacing these ideas of talking clearly and honestly to girls about their own desires and their own pleasures," she says.

Stay up-to-date with the latest news, stories and insider events.

Please enter a valid email addressOops, something went wrong!

You've signed up to receive emails. Please check your email for a welcome confirmation.

Then they go into puberty education class and girls have period and unwanted pregnancy, and you see only the inside anatomy, that thing that looks like a steer head, with the ovaries and everything, and then it greys out between the legs, so we never talk about the vulva, we never talk about the clitoris, very few girls explore, there's no self-knowledge, and then they go into their sexual experiences and we expect them to be able to have some sense of entitlement, some sense of knowledge, to be able to assert themselves, to have some sense of equality, and it's just not realistic that that's going to happen.

On whether kids are having more sex at a younger ageand the prevalence of oral sex

Kids are not having intercourse at a younger age, and they're not having more intercourse than they used to. They are engaging in other forms of sexual behavior, younger and more often. And one of the things that I became really clear on was that we have to broaden our definition of sex, because by ignoring and denying these other forms of sexual behavior that kids are engaging in we are opening the door to a lot of risky behavior, and we are opening the door to a lot of disrespect. ...

[Oral sex] is considered to be less intimate than intercourse, and something that girls say repeatedly to me would be, "It's no big deal." There's an argument that some of the girls have in the book about exactly what it is. Is it sex? Is it not sex? Is it no big deal? ... It was something that they felt that they could do that boys expected. That they could do to not have to do something else. It was a way that they could cultivate popularity, it was a way that they felt interestingly, they would talk about feeling more in control, than if it was reciprocal. ...

They felt it was safer sex, which is true and not true, because the rates of STDs have actually shot up among teenagers, even though the rates of intercourse have not, because they think that oral sex is safer sex and things like gonorrhea are spreading much more quickly.

On talking to girls about their partners not reciprocating oral sex

I starting saying, "Look, what if every time you were with a guy, he told you to go get him a glass of water from the kitchen and he never offered to get you a glass of water. Or if he did he'd say, "Ugh, you want me to get youa glass of water?" You would never stand for it! Girls, they would bust out laughing when I said that, and they'd say, "Oh, I never thought about it that way." I thought well, maybe you should if you think that being asked repeatedly to give someone a glass of water without reciprocation is less insulting than being asked to perform a sexual act over and over. ...

On what "hooking-up" means

It can mean anything. It can mean kissing, it can mean intercourse, it can mean any other form of sexual interplay. It really is a nonphrase. But what the hook-up culture means, I mean, kids did not invent casual sex, right? But what has changed is the idea that casual sex is the pathway to a relationship, that sex is a precursor rather than a function of intimacy and affection. ...

[In college] pretty much if you didn't want to stay home with microwave popcorn calling your parents, especially for freshman and sophomores, that was kind of what they did. They went out, they got drunk, they hooked up.

On drinking and hook-up culture

Hook-up culture particularly, it's not just lubricated by alcohol anymore, it's completely dependent on it. One sociologist told me that alcohol was what created this compulsory carelessness, so that it was a way to signal that the sex that they were having was meaningless. Alcohol, it was almost like it had replaced mutual attraction as kind of reason in and of itself to have sex, so it was a way to not care. It was a way to say, "We're just doing this for one night."

What was tricky was that both the thing that is held out for college students in particular, but high school students too, as "fun," which is getting drunk and hooking up, also facilitated assault, because alcohol is really the No. 1 date drug. ... We talk a lot about girls drinking and reducing girls drinking, and I think it's very important to talk to girls about the particular effects of alcohol on their bodies, because drink for drink, we get drunker faster than boys do.

We can't forget to talk about the impact of alcohol on boys, because we know that alcohol at best loosens inhibitions, it reduces a person's ability to read social cues, it gives young men who might not otherwise have it, courage is probably the wrong word, but the courage, I guess, to commit an assault, or to ignore "no," and tend to be more aggressive when they do. Alcohol also makes boys less likely to step in as bystanders when they see something occurring, than they would be if they were sober. So we really have to address both sides of this equation, if we want to reduce assault.

On the notion of multiple "virginities"

One girl said to me, "Usually the opposite of a negative is a positive, but when you're talking about girls and sex, the opposite of slut is prude, both of which are negative. So what are you supposed to do?" So they're always trying to walk this line where they're not considered slutty, but they're not considered too [much of a] prude. It's an ever-shifting kind of dynamic, so part of that was getting rid of virginity, which often was something they did drunk, not necessarily with someone they cared that much about, and you really have to ask, is that really experience? Is the person who rushes toward intercourse wasted getting more experience than the person who spends three hours making out with a partner sober and exploring ideas about sexual tension and pleasure and what feels good? We have this weird idea, and I think that our emphasis on virginity right now is not doing girls any favors, and of course it also completely disregards gay girls.

One of the things that was really great was in talking to a gay girl I asked her, "When did you think that you had lost your virginity?" And she said, "Well, you know, I really have thought a lot about that, and I'm not really sure." She gave a few different answers and then she said, "You know what I think? I think a girl loses her virginity when she has her first orgasm with a partner." And it completely knocked me out. I thought, "Wow." I know we're not going to dismantle the idea of virginity, but what if we could broaden it to think that there's multiple virginities, and what if that was one of them? That would totally shift our ideas of how we thought about girls and boys and sex.